Extreme-ultraviolet emission from cool star outer atmospheres

Abstract

view Abstract Citations (20) References (34) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Extreme-ultraviolet emission from cool star outer atmospheres. Landini, M. ; Monsignori Fossi, B. C. ; Paresce, F. ; Stern, R. A. Abstract EUV line and continuum emission spectra are computed for cool stars with varying levels of coronal and chromospheric activity. The stars' visible surfaces are seen as covered by a network of identical solar-like magnetic loop structures. The density and thermal structures of the loops are determined by stationary solutions of the appropriate coupled mass, momentum, and energy-balance equations including self-consistent convective, conductive, and radiative input and loss terms. The model's boundary conditions (coronal temperature, base pressure, and loop filling factor) are constrained by available IUE and Einstein measurements of the corresponding FUV and soft-X-ray emissivities. An integration of the differential emission measure along the loop folded through an optically thin low-density plasma-emissivity code yields the resultant 1-2000-A flux. Calculated loop models and associated EUV emission spectra for nominal-absorbing interstellar hydrogen corlum densities are given for Alpha Cen, the Hyades stars BD + 15 deg 640 and BD + 14 deg 693, and the very active triple star HD 165590. The important diagnostic features of the complex EUV emission spectra thus derived are briefly described. Publication: The Astrophysical Journal Pub Date: February 1985 DOI: 10.1086/162934 Bibcode: 1985ApJ...289..709L Keywords: Chromosphere; Cool Stars; Extreme Ultraviolet Radiation; Late Stars; Stellar Coronas; Ultraviolet Spectra; Coronal Loops; Emission Spectra; Thermal Plasmas; Triple Stars; Wavelengths; Astrophysics full text sources ADS | data products SIMBAD (5) MAST (1)